Transfer mechanism



Jan. 17, 1967 Filed Jan. 27, 1965 J. ALEXON 3,298,541

TRANSFER MECHANISM 2 Sheets-Sheet l Q Q 9 LL f INVENTCR.

JAMES ALEXON Hm Q ATTORNEY Jan. 17, 1967 J. ALEXON TRANSFER MECHANISM 2 SheeCs-She et 8 Filed Jan. 27, 1965 E ll n i i N GE 7. V NN INVENTOR.

JAMES ALEXON BY W 4M ATTORNEY United States Patent 3,2s,541 TRANSFER MECHANISM James Alexon, 21605 Benjamin, St. Clair Shores, Mich. 48081 Filed Jan. 27, 1965, Ser. No. 428,434 7 Claims. (31. 214 1 This invention relates to a mechanism for transferring workpieces progressively through a series of stations and more particularly to the type of transfer mechanism which employs a number of sets of tong-like fingers, each set adapted to open and close about a workpiece, all supported on a plate which is reciprocated in timed relation to the operation of a serviced machine.

Transfer device of this type are employed to service multiple station work forming and machining systems such as multiple station cold headers. The serviced machine automatically undergoes an operational cycle and the work fingers are opened and closed and transferred between adjacent stations in timed relation to the operation of the machine.

For example, a mechanism servicing four successive stations aligned lineally with respect to one another will employ a plate which journals eight shafts spaced at regular intervals along its length. Each of the shafts supports a radially extending work engaging arm and the arms are divided up into four sets each including two adjacent arms. These two adjacent arms are arranged in a tong-like relationship with their ends crossed and supporting work engaging pads which are directed toward one another. The work arms may extend beyond their shafts and be connected at their opposite extreme ends with springs which urge the work engaging ends into contact with one another, or alternatively some other suitable means may be provided for biasing the arms into a closed position. These spring means provide each arm pair With a neutral position wherein the arms are closed and the extensions of the arms beyond the pivoting shafts are spaced at a minimum distance from one another. Previous transfer devices of this type have provided contact members disposed on the shafts which connect successive sets of arms to transfer driving motion between the arms. One of the shafts was powered by the serviced machine so as to oscillate in timed relation to the operation of the machine. This oscillation would cause the pair of arms directly powered to open in timed relation. The springs would then close the arms when the driving force was removed. This motion was transferred to the other arms in the train by the contact mechanism.

Such systems were aligned by bringing their mechanisms into contact with one another and positioning the arms on the shafts so that they assumed a proper disposition. Each finger set was then in its neutral, closed position and the opening motion provided by the driven shaft would be supplied to all of the finger sets. However, when the contacting mechanisms between the shafts or the finger ends exhibited wear, a play would be introduced between successive finger pairs. This play would create delays in the transfer of the opening motion from the driven shaft down the train and would also decrease the distance by which the driven arms opened. The wear would stack up so that the last arm pair in the train would experience a driving force that was effected by the wear of all the previous elements in the train.

The board object of the present invention is to provide a transfer mechanism of the above type wherein means are provided for maintaining the arms pairs in driving contact with one another independently of any wear which may occur in their contacting surfaces. This object is broadly achieved by providing stop means operative to limit the motion of one of the arms in the train, preferably the driven arm, in its closed direction. The stop is adjusted 3,298,541 Patented Jan. 17, 1967 so that the arms are not in their neutral positions when the stop is reached but are rather urged by the springs against the stop. Then any wear which occurs between the driving connections will not create play but will be taken up by the spring means so that the arms remain in immediate driving contact with one another. When wear occurs in the contact means the arms will be displaced from their neutral position but they may be easily adjusted to their original positions by rotating them on their supporting shafts. With the present invention it is no longer necessary to replace the driving means as wear occurs. The present invention also greatly simplifies the process of adjusting the transfer mechanism to cooperation with the machine.

Another object of the present invention is to provide a connecting structure between the finger pairs which will greatly minimize the rate of Wear.

Other objects, advantages and applications of the present invention will be made apparent by the following detailed description of a preferred embodiment of the invention. The description makes reference to the accompanying drawings in which:

FIGURE 1 is a front view of a transfer mechanism constituting a preferred embodiment of the present invention;

FIGURE 2 is a top sectional view of the transfer mechanism taken along lines 2-2 of FIGURE 1;

FIGURE 3 is an elevational sectional view of the mechanism taken along line 3-3 of FIGURE 2; and

FIGURE 4 is a side view of the mechanism showing it in cooperating relation with the workpiece and the operating segments of the cold heading machine.

Referring to the drawings, the transfer mechanism is constructed of an elongated box consisting of a front plate 10, a back plate 12, a pair of side plates 14 and 16, and top and bottom plates 18 and 20. The front plate 10 is attached to the forward edges of the top, bottom and side plates by means of corner screws 22 and may be removed to gain access to the box. The front plate 10 is formed with eight bored holes 24 a, b, c, d, e, f, g and 72 arranged in a straight line along the length of the plate at an eleva-l tion slightly below the center of the plate. Each of these bores is fitted with a bushing 26 a, b, c d, e, f, g and h. The back plate 12 is formed with eight bores 28 a, b, c, a, e, f, g and h, and these bores have a diameter equal to the inner diameter of the bushings 26 and are arranged in direct alignment with the bored holes 24.

Eight shafts 30, 32, 34, 36, 38, 40, 42 and 44 are journaled in the bushings 26 and the opposite holes 28 and each of the shafts extends beyond the forward face of the front plate 10. The shafts 30, 34, 36, 40, 42 and 44 terminate at a line flush with the rear surface of the back plate 12 but the two shafts 32 and 38 extend for a distance beyond the back plate. Each of the shafts has a flat 46 formed on one side of its end which projects forward of the plate 10. Keys 48 are fitted in a keyways formed in each of the shafts at the inner end of the flat 46. The keyways are disposed so that the keys 48 extend transversely to the shaft.

The work gripping arms are identical with one another except that the two members of a pair are reversed. Each includes a hub member 50 having a central aperture 52 which fits about the shafts. A block 54 formed on the hub is tapped to receive a pair of set screws 56 which bear against the upper surface of the key 48 and allow the angular relation of the hub and the arm to be adjusted with respect to the shaft. An upper arm member 58 extends upwardly from the shaft 50 and connects to one end of a spring 60 at its upper end. The other shaft in each pair connects to the other end of that spring.

The hubs also carry downward extending arm members 62, the arm members of one set being off-set with respect 3 to one another so that they may cross. The ends of the downward extending arms carry jaw retainers 64. The actual workpiece jaws 66 and 68 are shaped to support the particular workpiece 70 which is to be transferred. The jaw retaining section 64 includes set screws 72 so that the jaws 66 and 68 may be changed. As is best seen in FIGURE 2 the jaw pairs supported on the shafts 30 and 32 and 38 and 40 are separated from the plate from the forward side of the plate by spacers 73 while the jaw pairs supported on shafts 34 and 36 and 42 and 44 are supported on spacers 74 which stagger the upper arm members 58 with respect to one another so that they may overlap as seen in FIGURE 1.

FIGURE 3 illustrates the contact members that drivingly connect the arm pairs to one another. The shafts 32, 36 and 42 each carry a first rocker type 89 within the box formed by the plates 10, I2, 14, l6, l8 and 20. The rocker members 80 have a pair of radially extending flats 82 which project in opposite directions from the shaft and a central aperture 84 which is passed over and rigidly fixed to the shaft. The shafts 34 and 40 carry similar rocker members 86 which are inverted with respect to the rocker members 80 and extend over them at their adjacent points. The rocker members 86 have extending arms 88 but these arms journal contact pins 90 which rotatably supported in the armsare prevented from withdrawing by roller pins'92. The roller pins 92 pass through the arms 88 and grooves formed in the rollers 92 to rotatably support them. The end shafts 30 and 44 carry rocker members 96 each having a single extending arm which supports rollers 90 and contacts the adjacent rocker members 80. The shaft 38 is equipped with a rocker member 100 which has a first arm 102 projecting upwardly on one side and a second arm 104 projecting downwardly on the other side. The arm 102 is equipped with a roller 90 and the other arm contacts the roller 99 supported on the rocker 86 of the shaft 40.

The shaft 38 is extended outwardly from the rear of the box and is connected to the operating machine by suitable mechanism which does not form a part of the present invention and is not described. This mechanism may be of any variety which is operative to cause the shaft 38 to rotate in the counterclockwise direction as viewed from FIGURE 1 when it is desired to open the jaws of the work holders. This rotation is transmitted by the extending arms 102 and 104 to the two adjacent rocking members supported on shafts 36 and 40, causing both of them to rotate in a clockwise direction. They in turn drive their next adjacent rockers to turn in the counterclockwise direction and so on through the chain, with alternate shafts moving in opposite directions. These rotations are such as to bring the arms 66 and 68 out of contact with one another so as to release any workpieces held therein and allow for the forming or machining ac tion. FIGURE 4 illustrates a typical action wherein a die 120 and a backing member 124 operate on a workpiece 70. In order to completely form the workpiece the arms 66 and 68 must be opened or they will be struck by the die. The rotation movement of the shaft 38 thus acts to open the arms.

When the force which causes the shaft 38 to rotate in the counterclockwise direction is terminated the shafts are rotated back to their original position because of the action of the springs 60. The entire chain is linked together by the rocker arms and the return motion is limited by a stop member 130 which is fixed to the inner side of the rear plate 12. In other embodiments of this invention this stop member 130 may be adjustable. When the upper side of the arm 102 of the rocker associated with the shaft 38 contacts the stop the motion of the entire chain is halted.

This stop member represents a very important aspect of the present invention. The stop member and its position with respect to the rocker arm 100 are adjusted so that when the arm reaches the stop the rocker extremities are all in contact with one another and are maintained in contact by the springs 60. If any wear occurs to the contacting section of the rocker arms the arms will be displaced from their neutral position; but they may be readjusted to their initial positions simply by adjusting the set screws 56 to rotate the arms on their shafts. No play will result between the rocker members as a result of wear.

In previous devices of this nature no stop means was provided for the arms in one position but each arm pair was rather allowed to float about its neutral position and the contact rockers were arranged so as to bring all the shafts into contact with one another in this position. However, any wear in the contact members resulted in play between the arm pairs allowing the arm pairs to cross the center line and intnoducing a delay in the transmission of the rotation of the driving shaft to the other arm pairs.

Appropriate mechanisms associated with the connecting machine, which does not form part of this present invention, causes the entire box to reciprocate along its longitudinal axis in timed relation to the motion of the machine. This reciprocation of course occurs in timed relation to the rotation of the shaft 38 by the associate ma chine so that the arms open and close and transfer in a timed sequence to produce motion of the workpieces 70 through the sequence of stations served by the transfer mechanism.

In order to adjust the transfer mechanism to the machine the rocker member is first rotated against the stop 130. Then the two end rockers 96 are rotated to take up the slack in the train. Then each arm is adjusted by the set screws 56 until it is in the proper position.

The extensions of the shaft 32 beyond the back plate 12 may be provided with suitable handle means (not shown) for manually opening the arms.

Having thus described my invention, I claim:

1. A transfer mechanism of the type described, comprising: a plate; a plurality of shafts journalled in said plate, the shafts being arranged with their center lines along a line path on said plate with their shafts extending normally to the plane of the plate; an arm fixed to and extending radially from each of the shafts, the arms being arranged in operative pairs consisting of two adjacent arms; means for urging each arm pair into a closed position wherein the ends of the arms tend to abut one another; rocker means connecting adjacent arms so as to transfer the motion of one of the shafts to all the other shafts, such motion being in such a direction as to move each arm pair against said means for urging; and fixed stop means adjacent said plate for limiting the motion of at least one arm against the urging means so as to maintain the rocker means in contact with one another independently of wear of the rocker means.

2. A transfer mechanism of the type described, comprising: a plate; a plurality of shafts journalled in said plate, extending normally to the plane of the plate, with their center lines disposed along a line path on said plate; an arm member attached to each of the shafts and extending radially therefrom, said arms being disposed in pairs each consisting of two adjacent arms; work holding means fixed to extreme ends of said arms; spring means for urging each arm pair into a closed position wherein the work holding means of a pair abut one another; rocker means connecting adjacent arms, so as to transfer a motion of one arm in the direction away from the abutment with its companion arm to all other arm pairs so as to move each of them away from contact with its companion arm; .and fixed stop means adjacent said plate for limiting the motion of at least one arm against the urging means so as to maintain the rocker means in contact with one another independently of wear of said rocker means.

3. The mechanism of claim 2 wherein the spring means for urging each arm pair into a closed position consists of one spring associated with each arm pair, each such spring having one end connected to one arm of the pair and the other end connected to the other arm of the pair.

4. The transfer mechanism of claim 3 wherein each arm includes an upper section which extends beyond its supporting shaft in the direction opposite to the extension of the arm from the shaft, and the spring means are connected to the arm at the extreme end of said upper extension.

5. A transfer mechanism of the type described, comprising: a plate; a plurality of shafts journalled in said plate and extending normally thereto, the center lines of said shafts being arranged along a line path on said plate; a plurality of arms, one attached to and extending radially one of said shafts, said arms including a work holding section which extends in one direction from said shaft and a spring receiving section which extends in the other direction from said shaft, said arms being associated in pairs consisting of two adjacent arms; a plurality of springs, each having one end attached to the spring receiving section of one arm in a pair and the other end attached to the spring receiving section of the other arm in a pair, said springs being operative to urge the work holding ends of said arms into a closed, neutral position; rocker means connecting adjacent arms so that the motion of one of the arms, in a direction away from its companion arm, is communicated to all the other arms, causing a similar motion of said other arms; and fixed stop means adjacent said plate for limiting the motion of at least one arm against its spring to maintain its arm pair out of the neutral position and to limit the other arms in the chain through said rocker means so that they are maintained out of their neutral positions and the rocker means are maintained in contact with one another independently of wear of said rocker means.

6. The transfer mechanism of claim 5 wherein the stop means is adjustable.

7. The transfer mechanism of claim 5 wherein each of the arm members is supported on a shaft member so that it may be adjusted radially with respect thereto.

References Cited by the Examiner UNITED STATES PATENTS 2,026,823 1/1936 Clouse 10-12 2,100,028 11/1937 Frayer 10-12 2,687,660 8/1954 Friedman l076 2,791,786 5/1957 Hoyt l012 3,165,766 1/1965 Wisebaker 1012 MARVIN A. CHAMPION, Primary Examiner. 

1. A TRANSFER MECHANISM OF THE TYPE DESCRIBED, COMPRISING: A PLATE; A PLURALITY OF SHAFTS JOURNALLED IN SAID PLATE, THE SHAFTS BEING ARRANGED WITH THEIR CENTER LINES ALONG A LINE PATH ON SAID PLATE WITH THEIR SHAFTS EXTENDING NORMALLY TO THE PLANE OF THE PLATE; AN ARM FIXED TO AND EXTENDING RADIALLY FROM EACH OF THE SHAFTS, THE ARMS BEING ARRANGED IN OPERATIVE PAIRS CONSISTING OF TWO ADJACENT ARMS; MEANS FOR URGING EACH ARM PAIR INTO A CLOSED POSITION WHEREIN THE ENDS OF THE ARMS TO ABUT ONE ANOTHER; ROCKER MEANS CONNECTING ADJACENT ARMS SO AS TO TRANSFER THE MOTION OF ONE OF THE SHAFTS TO ALL THE OTHER SHAFTS, SUCH MOTION BEING IN SUCH A DIRECTION AS TO MOVE EACH ARM PAIR AGAINST SAID MEANS FOR URGING; AND FIXED STOP MEANS ADJACENT SAID PLATE FOR LIMITING THE MOTION OF AT LEAST ONE ARM AGAINST THE URGING MEANS SO AS TO MAINTAIN THE ROCKER MEANS IN CONTACT WITH ONE ANOTHER INDEPENDENTLY OF WEAR OF THE ROCKER MEANS. 